Initial (Android only) implementation of a WebView widget.

packages/webview_flutter/android/src/main/AndroidManifest.xml

@@ -1,3 +1,4 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="io.flutter.plugins.webviewflutter">
+    <uses-sdk android:minSdkVersion="20" android:targetSdkVersion="26"/>
 </manifest>

packages/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/FlutterWebView.java

@@ -0,0 +1,48 @@
+package io.flutter.plugins.webviewflutter;
+
+import static io.flutter.plugin.common.MethodChannel.MethodCallHandler;
+import static io.flutter.plugin.common.MethodChannel.Result;
+
+import android.content.Context;
+import android.view.View;
+import android.webkit.WebView;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
+import io.flutter.plugin.platform.PlatformView;
+
+public class FlutterWebView implements PlatformView, MethodCallHandler {
+  private final WebView webView;
+  private final MethodChannel methodChannel;
+
+  FlutterWebView(Context context, BinaryMessenger messenger, int id) {
+    webView = new WebView(context);
+    methodChannel = new MethodChannel(messenger, "plugins.flutter.io/webview_" + id);
+    methodChannel.setMethodCallHandler(this);
+  }
+
+  @Override
+  public View getView() {
+    return webView;
+  }
+
+  @Override
+  public void onMethodCall(MethodCall methodCall, Result result) {
+    switch (methodCall.method) {
+      case "loadUrl":
+        loadUrl(methodCall, result);
+        break;
+      default:
+        result.notImplemented();
+    }
+  }
+
+  private void loadUrl(MethodCall methodCall, Result result) {
+    String url = (String) methodCall.arguments;
+    webView.loadUrl(url);
+    result.success(null);
+  }
+
+  @Override
+  public void dispose() {}
+}

packages/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/WebViewFactory.java

@@ -0,0 +1,21 @@
+package io.flutter.plugins.webviewflutter;
+
+import android.content.Context;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.common.StandardMessageCodec;
+import io.flutter.plugin.platform.PlatformView;
+import io.flutter.plugin.platform.PlatformViewFactory;
+
+public class WebViewFactory extends PlatformViewFactory {
+  private final BinaryMessenger messenger;
+
+  public WebViewFactory(BinaryMessenger messenger) {
+    super(StandardMessageCodec.INSTANCE);
+    this.messenger = messenger;
+  }
+
+  @Override
+  public PlatformView create(Context context, int id, Object args) {
+    return new FlutterWebView(context, messenger, id);
+  }
+}

packages/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/WebviewFlutterPlugin.java

@@ -1,25 +1,14 @@
 package io.flutter.plugins.webviewflutter;
 
-import io.flutter.plugin.common.MethodCall;
-import io.flutter.plugin.common.MethodChannel;
-import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
-import io.flutter.plugin.common.MethodChannel.Result;
 import io.flutter.plugin.common.PluginRegistry.Registrar;
 
 /** WebviewFlutterPlugin */
-public class WebviewFlutterPlugin implements MethodCallHandler {
+public class WebviewFlutterPlugin {
   /** Plugin registration. */
   public static void registerWith(Registrar registrar) {
-    final MethodChannel channel = new MethodChannel(registrar.messenger(), "webview_flutter");
-    channel.setMethodCallHandler(new WebviewFlutterPlugin());
-  }
-
-  @Override
-  public void onMethodCall(MethodCall call, Result result) {
-    if (call.method.equals("getPlatformVersion")) {
-      result.success("Android " + android.os.Build.VERSION.RELEASE);
-    } else {
-      result.notImplemented();
-    }
+    registrar
+        .platformViewRegistry()
+        .registerViewFactory(
+            "plugins.flutter.io/webview", new WebViewFactory(registrar.messenger()));
   }
 }

packages/webview_flutter/example/lib/main.dart

@@ -2,59 +2,51 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:flutter/material.dart';
-import 'package:flutter/services.dart';
 import 'package:webview_flutter/webview_flutter.dart';
 
-void main() => runApp(new MyApp());
+void main() => runApp(MaterialApp(home: new WebViewExample()));
 
-class MyApp extends StatefulWidget {
+class WebViewExample extends StatelessWidget {
   @override
-  _MyAppState createState() => new _MyAppState();
-}
-
-class _MyAppState extends State<MyApp> {
-  String _platformVersion = 'Unknown';
-
-  @override
-  void initState() {
-    super.initState();
-    initPlatformState();
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Flutter WebView example'),
+        // This drop down menu demonstrates that Flutter widgets can be shown over the web view.
+        actions: <Widget>[const SampleMenu()],
+      ),
+      body: WebView(
+        onWebViewCreated: _onWebViewCreated,
+      ),
+    );
   }
 
-  // Platform messages are asynchronous, so we initialize in an async method.
-  Future<void> initPlatformState() async {
-    String platformVersion;
-    // Platform messages may fail, so we use a try/catch PlatformException.
-    try {
-      platformVersion = await WebviewFlutter.platformVersion;
-    } on PlatformException {
-      platformVersion = 'Failed to get platform version.';
-    }
-
-    // If the widget was removed from the tree while the asynchronous platform
-    // message was in flight, we want to discard the reply rather than calling
-    // setState to update our non-existent appearance.
-    if (!mounted) return;
-
-    setState(() {
-      _platformVersion = platformVersion;
-    });
+  void _onWebViewCreated(WebViewController controller) {
+    controller.loadUrl('https://flutter.io');
   }
+}
+
+class SampleMenu extends StatelessWidget {
+  const SampleMenu();
 
   @override
   Widget build(BuildContext context) {
-    return new MaterialApp(
-      home: new Scaffold(
-        appBar: new AppBar(
-          title: const Text('Plugin example app'),
-        ),
-        body: new Center(
-          child: new Text('Running on: $_platformVersion\n'),
-        ),
-      ),
+    return PopupMenuButton<String>(
+      onSelected: (String value) {
+        Scaffold.of(context).showSnackBar(
+            new SnackBar(content: new Text('You selected: $value')));
+      },
+      itemBuilder: (BuildContext context) => <PopupMenuItem<String>>[
+            const PopupMenuItem<String>(
+              value: 'Item 1',
+              child: Text('Item 1'),
+            ),
+            const PopupMenuItem<String>(
+              value: 'Item 2',
+              child: Text('Item 2'),
+            ),
+          ],
     );
   }
 }

packages/webview_flutter/lib/webview_flutter.dart

@@ -4,13 +4,112 @@
 
 import 'dart:async';
 
+import 'package:flutter/foundation.dart';
+import 'package:flutter/gestures.dart';
 import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
 
-class WebviewFlutter {
-  static const MethodChannel _channel = MethodChannel('webview_flutter');
+typedef void WebViewCreatedCallback(WebViewController controller);
 
-  static Future<String> get platformVersion async {
-    final String version = await _channel.invokeMethod('getPlatformVersion');
-    return version;
+/// A web view widget for showing html content.
+class WebView extends StatefulWidget {
+  /// Creates a new web view.
+  ///
+  /// The web view can be controlled using a `WebViewController` that is passed to the
+  /// `onWebViewCreated` callback once the web view is created.
+  ///
+  /// The `gestureRecognizers` parameter must not be null;
+  const WebView({
+    Key key,
+    this.onWebViewCreated,
+    this.gestureRecognizers = const <OneSequenceGestureRecognizer>[],
+  })  : assert(gestureRecognizers != null),
+        super(key: key);
+
+  /// If not null invoked once the web view is created.
+  final WebViewCreatedCallback onWebViewCreated;
+
+  /// Which gestures should be consumed by the web view.
+  ///
+  /// It is possible for other gesture recognizers to be competing with the web view on pointer
+  /// events, e.g if the webview is inside a [ListView] the [ListView] will want to handle
+  /// vertical drags. The web view will claim gestures that are recognized by any of the
+  /// recognizers on this list.
+  ///
+  /// When this list is empty, the web view will only handle pointer events for gestures that
+  /// were not claimed by any other gesture recognizer.
+  final List<OneSequenceGestureRecognizer> gestureRecognizers;
+
+  @override
+  State<StatefulWidget> createState() => _WebViewState();
+}
+
+class _WebViewState extends State<WebView> {
+  @override
+  Widget build(BuildContext context) {
+    if (defaultTargetPlatform == TargetPlatform.android) {
+      return new GestureDetector(
+        // We prevent text selection by intercepting long press event.
+        // This is a temporary workaround to prevent a native crash on a second
+        // text selection.
+        // TODO(amirh): remove this when the selection handles crash is resolved.
+        // https://github.com/flutter/flutter/issues/21239
+        onLongPress: () {},
+        child: AndroidView(
+          viewType: 'plugins.flutter.io/webview',
+          onPlatformViewCreated: _onPlatformViewCreated,
+          gestureRecognizers: widget.gestureRecognizers,
+          // WebView content is not affected by the Android view's layout direction,
+          // we explicitly set it here so that the widget doesn't require an ambient
+          // directionality.
+          layoutDirection: TextDirection.rtl,
+        ),
+      );
+    }
+    return Text(
+        '$defaultTargetPlatform is not yet supported by the webview_flutter plugin');
+  }
+
+  void _onPlatformViewCreated(int id) {
+    if (widget.onWebViewCreated == null) {
+      return;
+    }
+    widget.onWebViewCreated(new WebViewController._(id));
+  }
+}
+
+/// Controls a [WebView].
+///
+/// A [WebViewController] instance can be obtained by setting the [WebView.onWebViewCreated]
+/// callback for a [WebView] widget.
+class WebViewController {
+  WebViewController._(int id) {
+    _channel = new MethodChannel(
+        'plugins.flutter.io/webview_$id', const StandardMethodCodec());
+  }
+
+  MethodChannel _channel;
+
+  /// Loads the specified URL.
+  ///
+  /// `url` must not be null.
+  ///
+  /// Throws an ArgumentError if `url` is not a valid URL string.
+  Future<void> loadUrl(String url) async {
+    assert(url != null);
+    _validateUrlString(url);
+    return _channel.invokeMethod('loadUrl', url);
+  }
+}
+
+// Throws an ArgumentError if url is not a valid url string.
+void _validateUrlString(String url) {
+  try {
+    final Uri uri = Uri.parse(url);
+    if (uri.scheme.isEmpty) {
+      throw new ArgumentError('Missing scheme in URL string: "$url"');
+    }
+  } on FormatException catch (e) {
+    throw new ArgumentError(e);
   }
 }